rule win_lurk_auto {

    meta:
        author = "Felix Bilstein - yara-signator at cocacoding dot com"
        date = "2026-09-17"
        version = "1"
        description = "Detects win.lurk."
        info = "autogenerated rule brought to you by yara-signator"
        tool = "yara-signator v0.6.0"
        signator_config = "callsandjumps;datarefs;binvalue"
        malpedia_reference = "https://malpedia.caad.fkie.fraunhofer.de/details/win.lurk"
        malpedia_rule_date = "20260916"
        malpedia_hash = "53a643781c18e08f4a50949af60172d837a0b6f6"
        malpedia_version = "20260917"
        malpedia_license = "CC BY-SA 4.0"
        malpedia_sharing = "TLP:WHITE"

    /* DISCLAIMER
     * The strings used in this rule have been automatically selected from the
     * disassembly of memory dumps and unpacked files, using YARA-Signator.
     * The code and documentation is published here:
     * https://github.com/fxb-cocacoding/yara-signator
     * As Malpedia is used as data source, please note that for a given
     * number of families, only single samples are documented.
     * This likely impacts the degree of generalization these rules will offer.
     * Take the described generation method also into consideration when you
     * apply the rules in your use cases and assign them confidence levels.
     */


    strings:
        $sequence_0 = { ff7508 ff15???????? 8b35???????? 50 ff7508 }
            // n = 5, score = 1100
            //   ff7508               | push                dword ptr [ebp + 8]
            //   ff15????????         |                     
            //   8b35????????         |                     
            //   50                   | push                eax
            //   ff7508               | push                dword ptr [ebp + 8]

        $sequence_1 = { 8b4508 5b 5f 5e c9 c3 55 }
            // n = 7, score = 900
            //   8b4508               | mov                 eax, dword ptr [ebp + 8]
            //   5b                   | pop                 ebx
            //   5f                   | pop                 edi
            //   5e                   | pop                 esi
            //   c9                   | leave               
            //   c3                   | ret                 
            //   55                   | push                ebp

        $sequence_2 = { 8b4d0c 6bc928 030d???????? 898d24fdffff }
            // n = 4, score = 800
            //   8b4d0c               | mov                 ecx, dword ptr [ebp + 0xc]
            //   6bc928               | imul                ecx, ecx, 0x28
            //   030d????????         |                     
            //   898d24fdffff         | mov                 dword ptr [ebp - 0x2dc], ecx

        $sequence_3 = { 8b4d0c 51 e8???????? 85c0 750a }
            // n = 5, score = 800
            //   8b4d0c               | mov                 ecx, dword ptr [ebp + 0xc]
            //   51                   | push                ecx
            //   e8????????           |                     
            //   85c0                 | test                eax, eax
            //   750a                 | jne                 0xc

        $sequence_4 = { 50 889df8fdffff e8???????? 83c40c 8d85f4fcffff 50 }
            // n = 6, score = 800
            //   50                   | push                eax
            //   889df8fdffff         | mov                 byte ptr [ebp - 0x208], bl
            //   e8????????           |                     
            //   83c40c               | add                 esp, 0xc
            //   8d85f4fcffff         | lea                 eax, [ebp - 0x30c]
            //   50                   | push                eax

        $sequence_5 = { 8955ec 8b45ec 0500800000 8945ec }
            // n = 4, score = 800
            //   8955ec               | mov                 dword ptr [ebp - 0x14], edx
            //   8b45ec               | mov                 eax, dword ptr [ebp - 0x14]
            //   0500800000           | add                 eax, 0x8000
            //   8945ec               | mov                 dword ptr [ebp - 0x14], eax

        $sequence_6 = { 8b4d0c 832700 832100 58 }
            // n = 4, score = 800
            //   8b4d0c               | mov                 ecx, dword ptr [ebp + 0xc]
            //   832700               | and                 dword ptr [edi], 0
            //   832100               | and                 dword ptr [ecx], 0
            //   58                   | pop                 eax

        $sequence_7 = { 0308 8b45e0 8908 eb1c 8b45e0 8b4dd8 0308 }
            // n = 7, score = 800
            //   0308                 | add                 ecx, dword ptr [eax]
            //   8b45e0               | mov                 eax, dword ptr [ebp - 0x20]
            //   8908                 | mov                 dword ptr [eax], ecx
            //   eb1c                 | jmp                 0x1e
            //   8b45e0               | mov                 eax, dword ptr [ebp - 0x20]
            //   8b4dd8               | mov                 ecx, dword ptr [ebp - 0x28]
            //   0308                 | add                 ecx, dword ptr [eax]

        $sequence_8 = { 8b4d0c 51 8b55ec 52 e8???????? 8945fc }
            // n = 6, score = 800
            //   8b4d0c               | mov                 ecx, dword ptr [ebp + 0xc]
            //   51                   | push                ecx
            //   8b55ec               | mov                 edx, dword ptr [ebp - 0x14]
            //   52                   | push                edx
            //   e8????????           |                     
            //   8945fc               | mov                 dword ptr [ebp - 4], eax

        $sequence_9 = { 8955ec 8b45ec 8945f8 8b4d10 }
            // n = 4, score = 800
            //   8955ec               | mov                 dword ptr [ebp - 0x14], edx
            //   8b45ec               | mov                 eax, dword ptr [ebp - 0x14]
            //   8945f8               | mov                 dword ptr [ebp - 8], eax
            //   8b4d10               | mov                 ecx, dword ptr [ebp + 0x10]

        $sequence_10 = { 50 50 ff15???????? 85c0 7405 8b45fc }
            // n = 6, score = 800
            //   50                   | push                eax
            //   50                   | push                eax
            //   ff15????????         |                     
            //   85c0                 | test                eax, eax
            //   7405                 | je                  7
            //   8b45fc               | mov                 eax, dword ptr [ebp - 4]

        $sequence_11 = { 83c410 85c0 75e7 53 53 56 }
            // n = 6, score = 800
            //   83c410               | add                 esp, 0x10
            //   85c0                 | test                eax, eax
            //   75e7                 | jne                 0xffffffe9
            //   53                   | push                ebx
            //   53                   | push                ebx
            //   56                   | push                esi

        $sequence_12 = { 7444 8b45c0 0fb700 3d4d5a0000 }
            // n = 4, score = 800
            //   7444                 | je                  0x46
            //   8b45c0               | mov                 eax, dword ptr [ebp - 0x40]
            //   0fb700               | movzx               eax, word ptr [eax]
            //   3d4d5a0000           | cmp                 eax, 0x5a4d

        $sequence_13 = { 8b4d0c 83e901 894d0c 85c0 0f846f010000 }
            // n = 5, score = 800
            //   8b4d0c               | mov                 ecx, dword ptr [ebp + 0xc]
            //   83e901               | sub                 ecx, 1
            //   894d0c               | mov                 dword ptr [ebp + 0xc], ecx
            //   85c0                 | test                eax, eax
            //   0f846f010000         | je                  0x175

        $sequence_14 = { 57 8b7d08 33f6 6a02 57 6a01 e8???????? }
            // n = 7, score = 800
            //   57                   | push                edi
            //   8b7d08               | mov                 edi, dword ptr [ebp + 8]
            //   33f6                 | xor                 esi, esi
            //   6a02                 | push                2
            //   57                   | push                edi
            //   6a01                 | push                1
            //   e8????????           |                     

        $sequence_15 = { f7ff 8a4415f0 320431 41 84c0 }
            // n = 5, score = 800
            //   f7ff                 | idiv                edi
            //   8a4415f0             | mov                 al, byte ptr [ebp + edx - 0x10]
            //   320431               | xor                 al, byte ptr [ecx + esi]
            //   41                   | inc                 ecx
            //   84c0                 | test                al, al

    condition:
        7 of them and filesize < 5316608
}